Project Summary/Abstract Children with speech sound disorder show diminished accuracy and intelligibility in spoken communication and may thus be perceived as less capable or intelligent than peers, even when they are of average or above-average intellectual ability. While most speech errors resolve by the late school-age years, up to 1-2% of individuals will continue to exhibit residual speech errors (RSE) throughout the lifespan [1]. These errors can limit participation in academic and social settings, with negative consequences for both socioemotional wellness and socioeconomic outcomes [2, 3, 4]. RSE is known to be particularly challenging to treat, with the result that speech-language pathologists (SLPs) often discharge these clients with their errors uncorrected. Both affected children/families and speech-language pathologists (SLPs) have highlighted the critical need for research to identify and disseminate more effective forms of treatment for children with RSE. New technologies have the potential to revolutionize both the development and delivery of interventions for speech disorders, but this possibility has seen very little systematic investigation to date. Previous lab-based research, including work by the PI [5, 6, 7, 8, 9], has documented the ef?cacy of speech treatment incorporating visual-acoustic biofeedback, in which a client views a computer-generated image of the acoustic signal of his/her speech and attempts to match a model representing correct production. However, translation of this research to clinical practice is limited at present by the cost of the technology. At the same time, there is a need for well-powered group studies to strengthen the evidence base supporting the ef?cacy of biofeedback, but large- scale speech treatment research is prohibitively expensive under current models. The long-term goal of this project is to address these clinical and research needs simultaneously. We propose to develop a ?exible mobile application that will make an evidence-based biofeedback treatment program widely available to clinicians and pa- tients/parents, and will also enable large-scale tests of hypotheses about intervention ef?cacy through distributed delivery of treatment following standardized protocols. We anticipate that by increasing access to biofeedback intervention while also strengthening the evidence base in support of this method, this project will greatly expand the number of clinicians adopting biofeedback and thus multiply the public health impact of this important line of clinical research.